In the modern period, the European dragon is typically depicted as a huge, fire-breathing, scaly, horned, lizard-like creature; the creature also has leathery, bat-like wings, four legs, and a long, muscular prehensile tail. Some depictions show dragons with feathered wings, crests, fiery manes, ivory spikes running down its spine, and various exotic decorations.

In folktales, dragon's blood often contains magical properties. For example, in the opera Siegfried, dragon's blood allows Siegfried to understand the language of the Forest Bird. The typical dragon protects a cavern or castle filled with gold and treasure and is often associated with a great hero who tries to slay it.

Though a winged creature, the dragon is generally to be found in its underground lair, a cave that identifies it as an ancient creature of earth. Possibly, the dragons of European and Mid-Eastern mythology stem from the cult of snakes found in religions throughout the world.

Mosaic of the third century BC from Kaulon (Magna Graecia, southern Italy )

The Latin word draco, as in the constellation, Draco, comes directly from Greekδράκων, (drákōn, gazer). The word for dragon in Germanic mythology and its descendants is worm (Old English: wyrm, Old High German: wurm, Old Norse: ormr), meaning snake or serpent. In Old English, wyrm means "serpent", and draca means "dragon". Finnishlohikäärme directly translated means "salmon-snake", but the word lohi- was originally louhi- meaning crags or rocks, a "mountain snake".[citation needed] The prefix lohi- in lohikäärme is also thought to derive from the ancient Norse word lógi, meaning "fire", as in Finnish mythology there are also references to "tulikäärme" meaning fire-snake, or fire-serpent.

Roman dragons evolved from serpentine Greek ones, combined with the dragons of the Near East, in the mix that characterized the hybrid Greek/Eastern Hellenistic culture. From Babylon, the muš-ḫuššu was a classic representation of a Near Eastern dragon. John's Book of Revelation—Greek literature, not Roman—describes Satan as "a great dragon, flaming red, with seven heads and ten horns". Much of John's literary inspiration is late Hebrew and Greek, but John's dragon is more likely to have come originally through the Near East.[2][3] In the Roman Empire, each military cohort had a particular identifying signum (military standard), after the Parthian and Dacian Wars of Trajan in the east, the Dacian Draco military standard entered the Legion with the Cohors Sarmatarum and Cohors Dacorum (Sarmatian and Daciancohorts)—a large dragon fixed to the end of a lance, with large, gaping jaws of silver and with the rest of the body formed of colored silk. With the jaws facing into the wind, the silken body inflated and rippled, resembling a windsock.[4]

Dragons are usually shown in modern times with a body like a huge lizard, or a snake with two pairs of lizard-type legs, and able to emit fire from their mouths. This is commonly referred to as a Fire-Breathing Dragon. The European dragon has bat-like wings growing from its back. A dragon-like creature with wings but only a single pair of legs is known as a wyvern. The European dragon are most associated with fire breathing.

It has been speculated that accounts of spitting cobras may be the origin of the myths of fire-breathing dragons.[5]

In Western folklore, dragons are usually portrayed as evil, with the exceptions mainly in Welsh folklore and modern fiction. This is in contrast to Asian dragons, who are traditionally depicted as more benevolent creatures. In the modern period, the European dragon is typically depicted as a huge fire-breathing, scaly and horned lizard-like creature, with (leathery, bat-like) wings, with four legs and a long muscular tail. It is sometimes shown with feathered wings, crests, fiery manes, ivory spikes running down its spine and various exotic colorations. Dragon's blood often has magical properties; for example, in the opera Siegfried it let Siegfried understand the language of the Forest Bird. The typical dragon protects a cavern or castle filled with gold and treasure and is often associated with a great hero who tries to slay it. Though a winged creature, the dragon is generally to be found in its underground lair, a cave that identifies it as an ancient creature of earth. Possibly, the dragons of European and Mid-Eastern mythology stem from the cult of snakes found in religions throughout the world.

Many European stories of dragons have them guarding a treasure hoard. Both Fafnir and Beowulf's dragon guarded earthen mounds full of ancient treasure. The treasure was cursed and brought ill to those who later possessed it.

English "dragon" derives (via Middle English, Old French, and Latin) from Dacian dracon, "serpent, dragon"; the Greek word derives from Indo-European *derk-, "to see", and may originally have meant something like "monster with the evil eye."[citation needed] Notwithstanding their folkloric associations, there is no etymological connection between dragons and the ghoulish figures known as draugar in Old Norse, who haunt rich burial mounds.

The poem Beowulf describes a draca (dragon) also as wyrm (worm, or serpent) and its movements by the Anglo-Saxon verb bugan, "to bend", and says that it has a venomous bite; all of these indicate a snake-like form and movement rather than with a lizard-like or dinosaur-like body as in later belief (though the dragon of Beowulf does show several features that would later become popularized with dragons–namely, it breathes fire–lives underground, and collects treasure).

Dragons of Slavic mythology hold mixed temperaments towards humans. For example, dragons (дракон, змей, ламя, (х)ала) in Bulgarian mythology are either male or female, each gender having a different view of mankind. The female dragon and male dragon, often seen as sister and brother, represent different forces of agriculture. The female dragon represents harsh weather and is the destroyer of crops, the hater of mankind, and is locked in a never-ending battle with her brother. The male dragon protects the humans' crops from destruction and is generally benevolent to humanity. Fire and water play major roles in Bulgarian dragon lore: the female has water characteristics, while the male is usually a fiery creature. In Bulgarian legend, dragons are three-headed, winged beings with snake's bodies.

In Bulgarian, Russian, Belarusian, Ukrainian, Bosnian, Serbian, and Macedonian lore, a dragon, or "змей" (Bulgarian: Змей), zmey (Russian: Змей), smok (Belarusian: Цмок), zmiy (Ukrainian: Змій), (Bosnian zmaj), (Serbian: змај or zmaj), zmej (Macedonian: змеј), is generally an evil, four-legged beast with few, if any, redeeming qualities. Zmeys are intelligent, but not greatly so, often demanding tribute from villages or small towns in the form of maidens (for food), or gold. Their number of heads ranges from one to seven or sometimes even more, with three- and seven-headed dragons being most common. The heads also regrow if cut off, unless the neck is "treated" with fire (similar to the hydra in Greek mythology). Dragon blood is so poisonous that Earth itself will refuse to absorb it. In Bulgarian mythology these dragons are sometimes good, opposing the evil Lamya /ламя/, a beast that shares a likeness with the zmey. The most famous Polish dragon (Polish: Smok) is the Wawel Dragon or Smok Wawelski, the Dragon of Wawel Hill. It supposedly terrorized ancient Kraków and lived in caves on the Vistula river bank below the Wawel castle. According to lore based on the Book of Daniel, it was killed by a boy who offered it a sheepskin filled with sulphur and tar. After devouring it, the dragon became so thirsty that it finally exploded after drinking too much water. In the oldest, XII century version of this tale, written by Wincenty Kadłubek.[9] dragon was defeated by two sons of a King Krak, Krakus II and Lech II. A metal sculpture of the Wawel Dragon is a well-known tourist sight in Kraków. It is very stylised, but, to the amusement of children, noisily breathes fire every few minutes. The Wawel dragon is also featured in many items of Kraków tourist merchandise. Dragon is the coat of arms of the Polish princes, Piasts of Czersk.[10]

Other dragon-like creatures in Polish folklore include the basilisk, living in cellars of Warsaw, and the Snake King from folk legends.

The Cuélebre, or Culebre, is a giant winged serpent in the mythology of Asturias and Cantabria in the north of Spain. It usually lives in a cave, guards treasures and keeps nymph-like beings called xanas or anjanas as prisoners. They are immortal; however, they still are subject to aging.

There is a legend that a dragon dwelled in the Peña Uruel mountain near Jaca saying that it could mesmerise people with its glance, so the young man who decided to kill the beast equipped himself with a shiny shield, such that the dragon's glance would be reflected. When the young man arrived at the cave where the dragon lived, he could kill it easily because the dragon mesmerised itself. This legend is very similar to the Greek myth of Medusa.

Herensuge is the name given to the dragon in Basque mythology, meaning "last serpent". The most famous legend has St. Michael descend from Heaven to kill it, but only once did God agree to accompany him in person. Sugaar, the Basque male god, is often associated with the serpent or dragon but able to take other forms as well. His name can be read as "male serpent".

Dragons are well known in Catalan myths and legends, in no small part because St. George (Catalan Sant Jordi) is the patron saint of Catalonia. Like most dragons, the Catalan dragon (Catalan drac) is an enormous serpent with two or, rarely, four legs and sometimes a pair of wings. As in many other parts of the world, the dragon's face may be like that of some other animal, such as a lion or bull. As is common elsewhere, Catalan dragons are fire-breathers, and the dragon-fire is all-consuming. Catalan dragons also can emit a fetid odor, which can rot away anything it touches.

The Catalans also distinguish a víbria or vibra (cognate with English viper and wyvern), a female dragon with two prominent breasts, two claws and an eagle's beak. Dracs, Víbries and other mythological figures used to participate in correfocs during popular celebrations.

In Portuguese mythology, coca[11] is a female dragon that battles Saint George on the Corpus Christi holiday. The fighting has a symbolic meaning: when the coca defeats Saint George the crops will be bad and there will be famine and death; when Saint George defeats the coca he cuts off her tongue and ears, the crops will have a good year and it announces prosperity. Still, she is called "saint" coca just as George is called saint, and the people cheer for her. Another dragon called drago is also represented in Portuguese mythology and used to take part in celebrations during the Middle Ages.

The legend of Saint George and the dragon is well known in Italy, but other saints are also depicted fighting dragons. For instance, the first bishop of the city of Forlì, Saint Mercurialis, was said to have killed a dragon and saved Forlì, so he is often depicted killing a dragon. Likewise, the first patron saint of Venice, Saint Theodore of Tyro, was a dragon-slayer, and a statue representing his slaying of the dragon still tops one of the two columns in St. Mark's square. St. Michael, the patron saint of paratroopers, is also frequently depicted slaying a dragon. Many dragons of the European Middle Ages were thought to be demonic or of evil status.

According to the Golden Legend, compiled by the Italian Jacobus de Voragine, Saint Margaret the Virgin was swallowed by Satan in the shape of a dragon, from whence she escaped alive when the cross she carried irritated the dragon's innards. The Golden Legend, in an atypical moment of scepticism, describes this last incident as "apocryphal and not to be taken seriously" (trans. Ryan, 1.369), which did not prevent the legend from being popular and getting artistic treatments.

Thyrus, the dragon of Terni

More prevalent are the legends about dragons in Italy, particularly in Umbria. One of the most famous dragons of Italian folklore is Thyrus, a wyvern that besieged Terni in the Middle Ages. One day, a young and brave knight of the noble House of Cittadini, tired of witnessing the death of his fellow citizens and depopulation of Terni, faced the dragon and killed him. From that day, the town assumed the creature in its coat of arms, accompanied by a Latin inscription: "Thyrus et amnis dederunt signa Teramnis", that stands under the banner of the town of Terni, honoring this legend.

Another poem tells of another dragon that lived near the village of Fornole, near Terni in the south of Umbria. Pope Sylvester I arrived in Umbria and freed the population of Fornole from the ferocity of the dragon, pacifying the dragon. Grateful for his deed, the population built a small church dedicated to the saint on the top of the mountain near the dragon's lair in the 13th century. In the apse of the church there is a fresco representing the iconography of the saint.

In England, to this day, a rampant red dragon (clutching a mace) is the heraldic symbol of the county of Somerset. The county once formed part of the early-medieval Anglo-Saxon kingdom of Wessex in western England, which too bore a dragon, or wyvern (a two-legged as opposed to a four-legged dragon), as a symbol. The Wessex beast is usually colored gold in illustrations.

According to the writer on heraldry Arthur Charles Fox-Davies, the red dragon of Wales originated with the standard of the 7th century king, Cadwaladr, and was used as a supporter by the Tudor dynasty (who were of Welsh origin).[12] Queen Elizabeth, however, preferring gold, changed the royal mantle and the dragon supporter from red to gold, and some Welsh scholars still hold that the dragon of Wales is properly ruddy gold rather than gules.[12] There may be some doubt of the Welsh origin of the dragon supporter of the Royal arms, but it certainly was used by King Henry III.[12]

A dragon was used as the crest of the Greater Royal Coat of Arms of Portugal since at least the 14th century. Later, two dragons were used as supporters of the shield of the Arms of Portugal. In the 19th century, King Peter IV of Portugal granted the city of Porto the incorporation of the dragon crest of the Royal Coat of arms in its municipal coat of arms, in gratitude for the support given to him by the city during the Liberal Wars. The badge of the F.C. Porto incorporates the old Porto municipal coat of arms with the dragon crest and this is why the dragon was adopted as the animal mascot of the club.

The emblem books popular from late medieval times through the 17th century often represent the dragon as an emblem of greed. The prevalence of dragons in European heraldry demonstrates that there is more to the dragon than greed.

A. Xaho, a romantic myth creator of the 19th century, fused these myths in his own creation of Leherensuge, the first and last serpent, that, in his newly coined legend, would arise again some time in the future bringing the rebirth of the Basque nation.

In the fantasy genre, there has been a trend of depicting dragons in a positive light: as allies instead of adversaries. Dragons are increasingly viewed as friends of humans and as highly intelligent and noble creatures, while still remaining the fearsome beasts of legend. They are frequently shown as guardians and close friends of individual humans. Many of these ideas were first popularised by Anne McCaffrey with her Dragonriders of Pern series, with later authors such as Christopher Paolini also depicting sympathetic dragon characters in Eragon. Ursula K. Le Guin created a meaningful image of dragons in her books about Earthsea. In George R. R. Martin's A Song of Ice and Fire, the character Daenerys Targaryen hatches three dragon eggs and raises the creatures as both her "children" and as the means with which she plans to regain the throne of her father. Dragons continue to be a popular subject for movies, such as the film How To Train Your Dragon, adapted from the book by Cressida Cowell, as well as the film series Shrek, and are particularly popular in multimedia fantasy franchises, most famously that of Warcraft, Demon's Souls and The Elder Scrolls V: Skyrim. Various characters in the Transformers franchise have been portrayed as having a dragon as their alternate mode, most commonly Megatron.